From patchwork Sun Feb 7 17:09:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ruan Shiyang X-Patchwork-Id: 12073201 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC5FAC433E0 for ; Sun, 7 Feb 2021 17:11:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9476C64DE8 for ; Sun, 7 Feb 2021 17:11:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229763AbhBGRKl (ORCPT ); Sun, 7 Feb 2021 12:10:41 -0500 Received: from mail.cn.fujitsu.com ([183.91.158.132]:52559 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229720AbhBGRKi (ORCPT ); Sun, 7 Feb 2021 12:10:38 -0500 X-IronPort-AV: E=Sophos;i="5.81,160,1610380800"; d="scan'208";a="104299368" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 08 Feb 2021 01:09:32 +0800 Received: from G08CNEXMBPEKD05.g08.fujitsu.local (unknown [10.167.33.204]) by cn.fujitsu.com (Postfix) with ESMTP id 641D84CE6F77; Mon, 8 Feb 2021 01:09:30 +0800 (CST) Received: from G08CNEXCHPEKD04.g08.fujitsu.local (10.167.33.200) by G08CNEXMBPEKD05.g08.fujitsu.local (10.167.33.204) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 8 Feb 2021 01:09:32 +0800 Received: from irides.mr.mr.mr (10.167.225.141) by G08CNEXCHPEKD04.g08.fujitsu.local (10.167.33.209) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Mon, 8 Feb 2021 01:09:31 +0800 From: Shiyang Ruan To: , , , CC: , , , , , , , , , , Goldwyn Rodrigues Subject: [PATCH 2/7] fsdax: Introduce dax_copy_edges() for CoW Date: Mon, 8 Feb 2021 01:09:19 +0800 Message-ID: <20210207170924.2933035-3-ruansy.fnst@cn.fujitsu.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210207170924.2933035-1-ruansy.fnst@cn.fujitsu.com> References: <20210207170924.2933035-1-ruansy.fnst@cn.fujitsu.com> MIME-Version: 1.0 X-yoursite-MailScanner-ID: 641D84CE6F77.ACBBD X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: ruansy.fnst@cn.fujitsu.com Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org dax_copy_edges() is a helper functions performs a copy from one part of the device to another for data not page aligned. Signed-off-by: Goldwyn Rodrigues Signed-off-by: Shiyang Ruan --- fs/dax.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/fs/dax.c b/fs/dax.c index b012b2db7ba2..ea4e8a434900 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1038,6 +1038,47 @@ static int dax_iomap_direct_access(struct iomap *iomap, loff_t pos, size_t size, return rc; } +/* + * Copies the part of the pages not included in the write, but required for CoW + * because offset/offset+length are not page aligned. + */ +static int dax_copy_edges(loff_t pos, loff_t length, struct iomap *srcmap, + void *daddr, bool pmd) +{ + size_t page_size = pmd ? PMD_SIZE : PAGE_SIZE; + loff_t offset = pos & (page_size - 1); + size_t size = ALIGN(offset + length, page_size); + loff_t end = pos + length; + loff_t pg_end = round_up(end, page_size); + void *saddr = 0; + int ret = 0; + + ret = dax_iomap_direct_access(srcmap, pos, size, &saddr, NULL); + if (ret) + return ret; + /* + * Copy the first part of the page + * Note: we pass offset as length + */ + if (offset) { + if (saddr) + ret = copy_mc_to_kernel(daddr, saddr, offset); + else + memset(daddr, 0, offset); + } + + /* Copy the last part of the range */ + if (end < pg_end) { + if (saddr) + ret = copy_mc_to_kernel(daddr + offset + length, + saddr + offset + length, pg_end - end); + else + memset(daddr + offset + length, 0, pg_end - end); + } + + return ret; +} + /* * The user has performed a load from a hole in the file. Allocating a new * page in the file would cause excessive storage usage for workloads with